Searched the forums and came up with nothing adequate.
My 34 MK1 with its t6.354 lost its tach awhile back. Been kinda doing research on this problem and going out quite a few times while doing so. Some people say the tach signal comes from the alternator and others say it comes from a sensor on the front by the injector pump. I haven't found anything like that. Anyway I'm inclined to believe it comes from the alternator as my batteries died. Took 2 weeks with the solar panel on the roof. Lucky i was in the harbor when she didnt turn over very fast. My question is does anyone have a part # or style or anything. Mine has nothing on it except it says Delco remy. I'm thinking it isn't even the correct alt because of the wire running out of the housing. Can anyone help me out? And yes I've done the obvious. Cleaned all connections,bypassed cables, etc. Just need the info for the alt and help with the tach information. Thank you

There is probably at least one alternator/starter rebuild guy near where you are. It costs less than $100 to get it completely overhauled. I found one five miles away. Also check an over the road truck repair place. They will have someone too.

When I had a Perkins, I was looking at a one for one replacement by (and I am going to horribly not remember the exact name) Leece-Neville/Prestolite. It will be an easy swap.

Don't go overboard upgrading the amperage unless you are going after changing out the wiring. If memory serves, mine was a 60A and I planned on only going up to 75A had I ever gotten to that project before we sold it.

On our Perkins the tach when out also, trace it to a burnt exciter/broken wire from the oil press sender. This wire allows the alternator to operate only after the motor has come up to oil pressure. Just replaced that wire and all has been fine.